This invention relates generally to methods and apparatus for feeding granulated material, and more specifically to a method and apparatus for cyclically metering and feeding charges of meltable granulated material to a heated reservoir that is particularly adapted for use in conjunction with an injection apparatus for molding investment casting patterns.
Injection apparatus of a type adapted automatically to inject wax blends in the production of investment casting patterns is disclosed in U.S. Pat. No. 3,806,875 issued Apr. 23, 1974. The apparatus includes a relatively large, heated, pressurized reservoir for receiving and maintaining molten a quantity of the wax-like or resinous material to be injected. It was the practice to fill the reservoir once or twice daily with relatively large quantities of the molten wax material which was melted elsewhere before being transported to the heated reservoir. The practice of pre-melting the injection material necessitated an extra operation and required additional heating equipment. It also presented certain difficulties in handling the molten material being transported and maintaining the material in the molten condition. A relatively large amount of the molten material must be stored in the reservoir until ready to be used. To maintain such a quantity of material in the molten condition necessitates the expenditure of relatively large amounts of heat energy.